1. Field of the Invention
The present invention relates to a synthetic resin container including a mouthpiece sealed by a closure, and a method for sealing the same. More specifically, it relates to a synthetic resin container including a mouthpiece sealed by a closure to be used for medical drip infusion or the like. The closure includes a tight-sealing synthetic resin stopper and a leakage preventing rubber stopper, and a method for sealing the same.
2. Description of the Prior Art
A synthetic resin container to be used for medical drip infusion or the like should be sealed by a closure capable of preventing liquid leakage even when an instillation needle or the like is inserted through the closure or is pulled out. To satisfy the above requirement, for example, a closure having a tight-sealing synthetic resin stopper and a leakage preventing rubber stopper has been employed.
Hitherto, such a synthetic resin container has been disclosed in, for example, Japanese Patent KOKOKU No. 3-28944, by the same inventor of the present invention. To seal the mouthpiece of the conventional synthetic resin container, first, the synthetic resin stopper is inserted into the mouthpiece, and the rubber stopper is then inserted into the synthetic resin stopper. Next, the top surfaces of the mouthpiece and the synthetic resin stopper, which are made flat, are covered with a metallic mouthpiece forming cap. Finally, by pressing the metallic mouthpiece forming cap using a welding heater, the mouthpiece and the synthetic resin stopper are pressed inwardly and thermally welded and integrated with each other and with the rubber stopper.
However, according to the prior art, each of the mouthpiece and the synthetic resin stopper has a flat top or upper surface. That is, the upper portions of the mouthpiece and the synthetic resin stopper are both solid. Due to such a configuration where two circular cylinders are solid, the thermal conductivity between the two circular cylinders is inferior. Thus, a problem arises because a long period of time is required for the thermal welding process.
Furthermore, the thermal welding process necessitates a welding heater and an additional power source. Thus, another problem arises in that the thermal welding process becomes complicated and consumes expressive energy.